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Yamuna, Thammarse S., Jerry P. Jasinski, Manpreet Kaur, Brian J. Anderson, and H. S. Yathirajan. "5-(4-Fluorophenyl)-2H-pyrazol-1-ium 2,2,2-trifluoroacetate." Acta Crystallographica Section E Structure Reports Online 70, no. 4 (March 15, 2014): o429—o430. http://dx.doi.org/10.1107/s1600536814005200.
The title salt, C9H8FN2+·C2F3O2−, crystallizes with two independent cations (AandB) and two independent anions (CandD) in the asymmetric unit. In the cations, the dihedral angles between the benzene and pyrazolium rings are 23.7 (3)° in cationAand 1.8 (8)° in cationB. In the crystal, each anion links to the two cationsviaN—H...O hydrogen bonds, forming a U-shaped unit with anR44(14) ring motif. These U-shaped units stack along theaaxis and are linkedviaC—H...O and C—H...F hydrogen bonds, forming slabs lying parallel to (100). Within the slabs there are π–π interactions between the pyrazolium rings [inter-centroid distance = 3.6326 (15) Å] and between the benzene rings [inter-centroid distance = 3.7244 (16) Å]. In the anions, the F atoms of the trifluoromethyl groups are disordered over two sets of sites, with refined occupancy ratios of 0.58 (3):0.42, 0.540 (14):0.46 (14), and 0.55 (2):0.45 (2) for anionC, and 0.73 (5):0.27 (5), 0.63 (5):0.37 (5), and 0.57 (8):0.43 (8) for anionD.
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Schefe, C. R., M. Watt, W. J. Slattery, and P. M. Mele. "Organic anions in the rhizosphere of Al-tolerant and Al-sensitive wheat lines grown in an acid soil in controlled and field environments." Soil Research 46, no. 3 (2008): 257. http://dx.doi.org/10.1071/sr07139.
Several sampling methods were investigated for the quantification of organic anions in the rhizosphere of Al-tolerant (ET8) and Al-sensitive (ES8) wheat plants in soil systems. Controlled environment studies used anion exchange membranes to collect rhizosphere organic anions (from root tips and mature regions of nodal roots) from ET8 and ES8 plants at the 6-leaf stage in a glasshouse environment. Using the anion exchange membranes, a selection of organic anions were detected on the tips and mature regions of roots, with ET8 and ES8 having similar rhizosphere organic anion profiles. The field experiment used 2 established methods of organic anion collection: rhizosphere soil and root washings. The ET8 and ES8 wheat lines had similar levels of organic anions, including malate, in the rhizosphere (using soil shaken from roots and root washings) at 3 sampling times (4 and 6 leaves, and flowering). The rhizosphere organic anions differed significantly from the bulk soil, with the concentration and range of organic anions in the rhizosphere decreasing towards flowering, presumably due to physiological changes in plant and root growth. This study used several techniques to investigate organic anion exudation by roots, with organic anions detected using all techniques. However, technical limitations of these techniques were recognised: (i) the lack of simultaneous exposure of root tips to both the anion exchange membrane and the chemical stimulant, e.g. Al3+; and (ii) the inability to derive the origin of organic anions measured in rhizosphere soil and root washings. The challenge for future soil-based organic anion research is to identify the dominant stress that has triggered an exudation response (i.e. Al toxicity, P deficiency), and to clearly differentiate between plant- and microbial-derived contributions to exudation.
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Parthé, Erwin. "Crystal chemical information to be obtained from the bond-number equality concept." Acta Crystallographica Section B Structural Science 62, no. 2 (March 15, 2006): 335–37. http://dx.doi.org/10.1107/s0108768106003065.
Based on the bond-number equality concept an equation is derived for anion complexes of normal valence compounds with triangularly and/or tetrahedrally coordinated central atoms and anions having one, two, three and four bonds to central atoms: %Δ = 4 − (n/m′) × [2 − %A [1] + %A [3] + 2 × %A [4]]. %Δ is the ratio of the number of central atoms with triangular anion coordination to the sum of all central atoms in the anion complex. n/m′ is the ratio of the number of all A anions to the number of all central atoms C′ in the anion complex. %A [1] is the ratio of the number of anions with one bond to a central atom to the sum of all anions in the anion complex. %A [3] and %A [4] are defined accordingly. The equation can be used to formulate the possible crystal chemical formulae, which are characterized by partitions of central atoms and anions according to their bond numbers. Nitridosilicates and selected oxoborates are treated as examples of applications of the equation.
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Li, Lei, Yu-Jian Hong, Dong-Yang Chen, Wang-Chuan Xiao, and Mei-Jin Lin. "Anion–π interactions in lithium–organic redox flow batteries." Chemical Communications 55, no. 16 (2019): 2364–67. http://dx.doi.org/10.1039/c8cc09834d.
The interactions between the electrolyte anions and electron-deficient redox-active organic molecules (anion–π interactions) have strong influences on the battery properties due to the anion–π-induced formation of radical anions or sandwich-like aggregates.
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Wilkinson, Hazel S., and William T. A. Harrison. "Hexane-1,6-diammonium bis(dihydrogenarsenate): infinite anionic layers containing R 6 6(24) loops." Acta Crystallographica Section E Structure Reports Online 63, no. 3 (February 28, 2007): m902—m904. http://dx.doi.org/10.1107/s1600536807007672.
The title compound, C6H18N2 2+·2H2AsO4 −, contains a network of doubly protonated centrosymmetric hexane-1,6-diammonium cations and dihydrogenarsenate anions. These species interact by way of cation-to-anion N—H...O and anion-to-anion O—H...O hydrogen bonds, the latter leading to infinite sheets of the H2AsO4 − anions.
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Salhany, James M. "Anion binding characteristics of the band 3 / 4,4'-dibenzamidostilbene-2,2'-disulfonate binary complex: Evidence for both steric and allosteric interactions." Biochemistry and Cell Biology 77, no. 6 (December 1, 1999): 543–49. http://dx.doi.org/10.1139/o99-061.
A novel kinetic approach was used to measure monovalent anion binding to better define the mechanistic basis for competition between stilbenedisulfonates and transportable anions on band 3. An anion-induced acceleration in the release of 4,4prime-dibenzamidostilbene-2,2prime-disulfonate (DBDS) from its complex with band 3 was measured using monovalent anions of various size and relative affinity for the transport site. The K1/2 values for anion binding were determined and correlated with transport site affinity constants obtained from the literature and the dehydrated radius of each anion. The results show that anions with ionic radii of 120-200 pm fall on a well-defined correlation line where the ranking of the K1/2 values matched the ranking of the transport site affinity constants (thiocyanate < nitrate equivalent to bromide < chloride < fluoride). The K1/2 values for the anions on this line were about 4-fold larger than expected for anion binding to inhibitor-free band 3. Such a lowered affinity can be explained in terms of allosteric site-site interactions, since the K1/2 values decreased with increasing anionic size. In contrast, iodide, with an ionic radius of about 212 pm, had a 10-fold lower affinity than predicted by the correlation line established by the smaller monovalent anions. These results indicate that smaller monovalent anions have unobstructed access to the transport site within the band 3 / DBDS binary complex, while iodide experiences significant steric hindrance when binding. The observation of steric hindrance in iodide binding to the band 3 / DBDS binary complex, but not in the binding of smaller monovalent anions, suggests that the stilbenedisulfonate binding site is located at the outer surface of an access channel leading to the transport site.Key words: band 3, anion transport, membrane protein structure, red cell membrane.
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Attiogbe, Francis K., Samar K. Bose, Wei Wang, Alastair McNeillie, and Raymond C. Francis. "The peroxymonocarbonate anions as pulp bleaching agents. Part 1. Results with lignin model compounds and chemical pulps." BioResources 5, no. 4 (August 18, 2010): 2208–20. http://dx.doi.org/10.15376/biores.5.4.2208-2220.
The peroxymonocarbonate mono-anion (HCO4─) is generated when the bicarbonate anion is added to a H2O2 solution. The mono-anion is believed to have a pKa value of ca. 10 and as such would start dissociating to the di-anion (CO42─) at pH ca. 8. The mono-anion should demonstrate electrophilic properties, while the di-anion should be a nucleophile. In an alkaline, non-sulfur pulping process such as soda/AQ, Na2CO3 could be obtained from the chemical recovery system and carbonated with CO2 from a flue gas stream to produce NaHCO3. In such a case only H2O2 would need to be purchased to generate the peroxymonocarbonate (PMC) anions. Bicarbonate anions could also be produced from the carbonation of solutions containing NaOH, Mg(OH)2 or mined Na2CO3. One or both of the PMC anions was found to be effective in oxidizing two lignin model compounds as well as lowering the lignin content of kraft and soda/AQ hardwood pulps. The PMC anions were generated in-situ by NaHCO3 or Na2CO3 + CO2 addition to dilute H2O2 solutions.
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Kovanda, František, Eva Kovácsová, and David Koloušek. "Removal of Anions from Solution by Calcined Hydrotalcite and Regeneration of Used Sorbent in Repeated Calcination-Rehydration-Anion Exchange Processes." Collection of Czechoslovak Chemical Communications 64, no. 9 (1999): 1517–28. http://dx.doi.org/10.1135/cccc19991517.
Synthetic hydrotalcite calcined at 350-550 °C was used for the removal of arsenate, chromate, and vanadate ions from water solutions. The initial anion concentrations were 0.002 mol l-1. The sorption isotherms were measured at 20 °C and at neutral pH. The Langmuir adsorption isotherm was used for the sorption capacity evaluation. The ability of the calcined hydrotalcite to remove the anions from solution decreased in the order of vanadate - arsenate - chromate. The hydrotalcite calcined at 450 °C exhibited the best sorption ability for all the anions. The sorbed anions were released by anion exchange in a carbonate-containing solution and the hydrotalcite after subsequent calcination was used again for the removal of anions. The repeating cycles calcination-rehydration-anion exchange gradually reduced the adsorption capacity of the hydrotalcite. The sorption capacity decreased by 50% after the first two cycles but it did not change significantly in the subsequent cycles. When chromate anions were adsorbed, the decrease in sorption capacity was not observed during repeated calcination-rehydration-anion exchange cycles. The change in the sorption capacity was influenced by the ability of calcined hydrotalcite to regenerate the layered crystal structure during the rehydration process.
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Yuan, Dan, and Yuan Fang Li. "Carboxyphenyl-terpyridine-based series of gels for procedural visual recognition of multi-anions." Analytical Methods 10, no. 41 (2018): 5032–37. http://dx.doi.org/10.1039/c8ay01679h.
The gelation of 4-[2,2′:6′,2′′-terpyridine]-4′-ylbenzoic acid (Hcptpy) occurred with various metal ions and specific anions. With the gel formation, corresponding metal ions and anions were recognized. Also, the metal–organic gels (MOGs) possess stimuli response property to anions. A step-by-step anion recognition progress was established based on one Hcptpy ligand and realized the selective identification 12 kinds of anions.
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McCarty, Nael A., and Zhi-Ren Zhang. "Identification of a region of strong discrimination in the pore of CFTR." American Journal of Physiology-Lung Cellular and Molecular Physiology 281, no. 4 (October 1, 2001): L852—L867. http://dx.doi.org/10.1152/ajplung.2001.281.4.l852.
The variety of methods used to identify the structural determinants of anion selectivity in the cystic fibrosis transmembrane conductance regulator Cl− channel has made it difficult to assemble the data into a coherent framework that describes the three-dimensional structure of the pore. Here, we compare the relative importance of sites previously studied and identify new sites that contribute strongly to anion selectivity. We studied Cl−and substitute anions in oocytes expressing wild-type cystic fibrosis transmembrane conductance regulator or 12-pore-domain mutants to determine relative permeability and relative conductance for 9 monovalent anions and 1 divalent anion. The data indicate that the region of strong discrimination resides between T338 and S341 in transmembrane 6, where mutations affected selectivity between Cl− and both large and small anions. Mutations further toward the extracellular end of the pore only strongly affected selectivity between Cl− and larger anions. Only mutations at S341 affected selectivity between monovalent and divalent anions. The data are consistent with a narrowing of the pore between the extracellular end and a constriction near the middle of the pore.
Each of my four main areas of work is concerned with the formation and further reactions of organic fluorinated anions. a) We have investigated the fluoride ion induced reactions of 2H-pentafluoropropene with some perfluoro-aromatic compounds, forming a series of aryl substituted carbon acids and their corresponding carbanions. Also included is a study of an unusual product that was formed with pentafluoronitrobenzene as the aromatic substrate. b) Some fluorinated dienes have been generated from the fluoride ion induced reactions of dimethylacetylenedicarboxylate with a series of cyclic fluorinated alkenes. With perfluorocyclohexene, a variable temperature n.m.r. investigation indicated that one of the products was fluxional at room temperature. Products derived from, perfluorocyclopentene were then further reacted with mono- and bi-functional nucleophiles forming some new products including some interesting polycyclic compounds. c) We have studied the fluoride ion induced reactions of malononitrile and phenylsulphonylacetonitrile with a range of polyfluorinated aromatic and heteroaromatic systems. This study has yielded a series of stable fluorinated organic caesium salts which could be crystallised. Acidification of these salts yielded a series of conjugate acids and some acidity measurements were made. Analysis of n.m.r. data has shed some light on the n.m.r. consequences of tautomerisation which was observed in some of the conjugate acids. A highly unusual carbon-13 n.m.r. concentration effect was studied for several pyrimidyl salts in perdeuteroacetone solution. d) The reaction of bifunctional carbon acids with fluorinated dienes has been used to develop a route to new pentadienyl anions, cyclopentadienes, and cyclopentadienyl anions. FAB mass spectroscopy has proved to be an important tool in the study of our anionic species. Some unusual thermal isomerisation behaviour of the new cyclopentadienes has also been observed and investigated.
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Wang, Zhiming 1958. "Anion Exchange and Competition in Layered Double Hydroxides." Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc332481/.
Exchange reactions of anions, especially ferrocyanide and carbonate, with layered double hydroxides (LDHs) were investigated in relation to the origin of life on the early Earth. The effect on ferrocyanide exchange of concentration, pH, reaction time and cations are discussed. It was found that there were two different kinds of ferrocyanide species: one was that intercalated into the layered structure, occupying a site of D symmetry within the LDHs, while in the other, the ferrocyanide group retains full O symmetry. In addition, very low concentration, ferrocyanide associated with LDH will change its FTIR absorption shape. Carbonate was much more strongly intercalated than ferrocyanide into the LDHs, probably because of the strong hydrogen bonding.
Gillmore, Jason G. Jr. "Evaluation of 1,1-Dimethyl-5,7-Di-T-Butylspiro[2.5]Octa-4,7-Dien-6-One as a Mechanistic Probe for Single Electron Transfer." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36888.
Single electron transfer (SET) mechanisms are becoming ubiquitous in modern
organic chemistry. However, it is often difficult to distinguish SET mechanisms from
polar mechanisms. Kinetics, products and product distributions, and response to
perturbation in solvent and substituents are often identical between the two mechanisms.
Detection techniques such as EPR, CIDNP, and UV absorption can often detect "blind"
pathways and thus cannot provide unambiguous evidence regarding the true mechanism
of interest. In recent years mechanistic probes have been developed which can test for
single electron transfer in the mechanism of interest in a more unambiguous manner,
although a given probe is often applicable to a narrower range of reactions.
In this work 1,1-dimethyl-5,7-di-t-butylspiro[2.5]octa-4,7-dien-6-one (6) is
presented as a new "hypersensitive" probe for single electron transfer to conjugated
carbonyl compounds. This new probe functions in a rather unique fashion, allowing
interpretation of the mechanism at work on the basis of the regiochemistry of spirocyclic
ring opening. This "regiodifferentiation" based probe was studied with a variety of
nucleophiles (particularly Grignard reagents) and has been found to be effective in
differentiating SET from polar processes, although surprising results indicative of polar
pathways in the case of reaction of 6 with Grignard reagents other than methyl Grignard
were found. Additional insight into the mechanism of the reaction of Grignard reagents
with conjugated ketones is also presented.
Master of Science
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Wells, Debra J. "Extraction of the perrhenate and pertechnetate anions from aqueous solutions using inorganic anion exchangers." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306851.
Brooks, Simon James. "From linear to cyclic anion receptors : high affinity receptors and sensors for oxo-anions." Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438694.
Guangliang, Chen. "The Dissociation of Metalloporphyrin Anions." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32517.
ESI-MS spectra of Ni(II), Co(III), Mg(III), and Fe(II) porphyrin solutions in methanol show porphyrin monomer species with different charge states, such as [Ni(II)TPPS+H]3-, [Co(III)TPPS]3-, [Mn(III)TPPS]3-, [Mn(III)TPPS+H]2-, [Fe(II)TPPS+H]3-, and [Fe(II)TPPS+2H]2- ions. Collision-induced dissociation (CID) of these monomer species produced primarily losses of neutral SO3 and SO2. The mechanisms, in which these dissociation pathways took place, were investigated by the means of DFT calculations of the corresponding dissociation of neutral and ionized benzenesulfonate (B3-LYP/6-31+G(2d, p) level) and porphyrin monomer (B3-LYP/6-31+G(2d, p)+LANL2DZ//PM7 level). RRKM fitting of the CID breakdown curves showed that the activation energies of the reactions that experience a loss of SO2 from [Co(III)TPPS]3- and [Mn(III)TPPS]3- were similar, but of a lower magnitude than those for a loss of SO3. On the other hand, for [Ni(II)TPPS+H]3- and [Fe(II)TPPS+2H]2-, the activation energies of the reaction leading to a loss of SO2 were also similar, but this time were larger than those leading to SO3 loss. These results are consistent with a mechanism by which the SO2 loss starts with -C6H4SO3-, while the SO3 loss has to begin with -C6H4SO3H. To lose this SO3, extra energy is required for [Co(III)TPPS]3- and [Mn(III)TPPS]3- in order for them to overcome the barrier of H transfer from the porphyrin ring to -SO3-, but this is irrelevant when it comes to [Ni(II)TPPS+H]3- and [Fe(II)TPPS+2H]2- since the C6H4SO3H moiety already exists. In addition, the reaction of [Fe(II)TPPS+H]3- losing H leads to a unique dissociation mechanism.
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Newington, Ian M. "Azo-anions in organic synthesis." Thesis, University of Oxford, 1985. http://ora.ox.ac.uk/objects/uuid:690ab891-be13-4582-a029-47974d20adac.
Novel synthetic applications of ambident azo-anions derived from hindered hydrazones have been investigated. Reaction with electrophiles occurred predominantly at carbon as the N-addition pathway was sterically retarded. Trityl, diphenyl-4-pyridylmethyl (DPP) benzhydryl, and t-butyldiphenylmethyl (BDP) hydrazones of various aldehydes and ketones were prepared in good yields from the corresponding hydrazines and carbonyls in aqueous methanol. The lithium salts derived from trityl and DPP hydrazones, by treatment with methyl lithium at -55°C, reacted with aldehydes and ketones to generate azo-alkoxides. These could be diverted to alcohols,by sequential protonation and spontaneous homolysis (about -20°C) in the presence of ethanethiol, or to alkenes,by treatment with phosphorus trichloride at -78 G followed by azo-homolysis. The reactions enabled efficient reductive cross-coupling of aldehydes and ketones. The mechanism of the alkene forming reaction was investigated. Anions of benzhydryl hydrazones were found to react inefficiently by a G-addition pathway giving mainly N-addition products. Anions of BDP hydrazones conveniently gave excellent yields of azo-alkanes upon treatment with alkyl halides,but no products were obtained on reaction with carbonyl electrophiles. The azo-alkanes could be isolated and purified and acted as key intermediates for several synthetically useful transformations. Homolysis in refluxing benzene with thiophenol gave alkanes in good yields. Phenylselenenyl-, bromo-, and chloro-alkanes,and β-alkylstyrenes were generated when thiol was replaced by diphenyl diselenide, N-bromosuccinimide, N-chlorosuccinimide and β-nitrostyrene respectively. Treatment of the azo-alkanes with trifluoroacetic acid generated benzophenone alkylhydrazones. These were dissolved in ethanol with concentrated hydrochloric acid, thereafter hydrolysis yielded alkylhydrazines or treatment with hydrogen (1 atm., 50°C, 20h) over 10% Pd/C generated primary amines by a novel use of carbonyls as α-aminocarbanion equivalents.
A, Moyer Bruce, Singh Raj Pal 1951-, and American Chemical Society Meeting, eds. Fundamentals and applications of anion separations. New York: Kluwer Acadamic/Plenum, 2004.
Charnley, Steven. "Anions." In Encyclopedia of Astrobiology, 46. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-11274-4_80.
Präsang, Carsten, and David Scheschkewitz. "Silyl Anions." In Functional Molecular Silicon Compounds II, 1–47. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/430_2013_104.
Crompton, Thomas Roy. "Organic Anions." In Determination of Anions, 453–68. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-61419-4_10.
Chivers, T. "Heteropolyatomic Anions." In Inorganic Reactions and Methods, 41–42. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145197.ch52.
Yamashita, Makoto, and Kyoko Nozaki. "Boryl Anions." In Synthesis and Application of Organoboron Compounds, 1–37. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-13054-5_1.
Miller, H. C., E. L. Muetterties, J. L. Boone, P. Garrett, and M. F. Hawthorne. "Borane Anions." In Inorganic Syntheses, 81–91. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470132418.ch16.
Crompton, Thomas Roy. "Preconcentration of Anions." In Determination of Anions, 555–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-61419-4_14.
Crompton, Thomas Roy. "Halogen-Containing Anions." In Determination of Anions, 58–139. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-61419-4_2.
Crompton, Thomas Roy. "Nitrogen-Containing Anions." In Determination of Anions, 140–277. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-61419-4_3.
Alves, Adrielly, and Régis Casimiro Leal. "Theoretical study of the mechanism of chromogenic chemodosimeters in the detection of sulfhydryl (SH–) and hydroxyl (OH–) anions." In VIII Simpósio de Estrutura Eletrônica e Dinâmica Molecular. Universidade de Brasília, 2020. http://dx.doi.org/10.21826/viiiseedmol2020128.
Sulfide (S2−) is a biologically and environmentally important anion. Exposure to the sulfide anion can cause chronic, respiratory diseases and irritations in the skin and mucous membranes. The protonated HS− or H2S forms are more toxic than the S2− itself. A derivative of the family of 2,4,6-triaryl-pyrylium cations bearing an amine in the para position of the 4-aryl group is sensitive for detecting sulfide anions in solution. Through DFT calculations, performed at level B3LYP/6-31+G(d) in gas phase, these authors present the thermodynamic stability of the interaction of chemodosimeters derived from the pyrilium and thiopirilium cation with hydroxyl (OH–) and sulfhydryl (SH–) anions.
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Ge, Xiaojing, Ghith Biheri, Abdulmohsin Imqam, Baojun Bai, and Yuwei Zhang. "Experimental Study: Investigating the Anions and Cations’ Effects on the Elasticity of the Anionic and Cationic High Viscosity Friction Reducers." In SPE Western Regional Meeting. SPE, 2023. http://dx.doi.org/10.2118/213048-ms.
Abstract High viscosity friction reducers (HVFRs) are widely used as friction-reducing agents and proppant carriers during hydraulic fracturing. The reuse of produced water has gained popularity due to environmental and economic benefits. Currently, the field’s most commonly used friction reducers are anionic and cationic HVFRs. Anionic HVFRs are typically pumped with freshwater, while cationic HVFRs are used with high Total Dissolved Solids (TDS) produced water. Cationic friction reducers are believed to have better TDS tolerance, friction reduction performance, and proppant transport capabilities compared to anionic friction reducers under high TDS conditions due to their superior viscoelastic properties. In addition, the impact of different anions and cations on the viscosity of HVFRs has been thoroughly studied, and viscosity reduction mechanisms include charge shielding, increasing the degree of hydrolysis, and forming coordination complexes. However, anions and cations’ effects on the elasticity of HVFRs still remain to be investigated. Besides, most previous experimental studies either do not specify experimental procedures or control the experimental variables well. Therefore, the ultimate objective of this experimental study is to analyze various cations and anions’ effects on the elasticity of anionic and cationic HVFRs comparably and precisely with experimental variables well controlled. Two hypotheses based on anions and cations’ effects on the viscosity of HVFRs are proposed and will be tested in this study. First, the elasticity reduction of anionic HVFRs is mainly due to cations, whereas the elasticity reduction of cationic HVFRs is mainly due to anions. Second, the salts’ effects on the elasticity reduction of HVFRs should follow the same trend as the salts’ effects on the viscosity reduction of HVFRs. For anionic HVFRs, monovalent Alkali metals should have a similar effect; divalent Alkaline earth metals should have a similar effect; transition metals should have the most severe effect. For cationic HVFRs, SO42- should have more pronounced effects than Cl-. To demonstrate both hypotheses, an anionic and a cationic HVFR at 4 gallons per thousand gallons (GPT) were selected and analyzed. The elasticity measurements of both anionic and cationic HVFRs were conducted with deionized (DI) water and various salts respectively. Fe3+ and H+ (or pH) effects were specifically investigated. The results showed both hypotheses were accepted.
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BAWIN, M., SIDNEY A. COON, and BARRY R. HOLSTEIN. "ANIONS AND ANOMALIES." In The Festschrift in Honor of Bruce H J Mckellar and Girish C Joshi. WORLD SCIENTIFIC, 2007. http://dx.doi.org/10.1142/9789812770301_0003.
Campo-Cacharrón, Alba, Jesús Rodríguez-Otero, and Enrique Cabaleiro-Lago. "Interaction between anions and naphthalendiimides." In The 14th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2010. http://dx.doi.org/10.3390/ecsoc-14-00472.
Castleman, A. Welford, C. R. Albertoni, K. Marti, D. E. Hunton, and R. G. Keesee. "Photodissociation dynamics of cluster anions." In International Laser Science Conference. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/ils.1986.jfc7.
Studies of the dissociation dynamics of cluster ions provide insight into the process of energy disposal for mass-selected species. Detailed investigations of the photodissociation of the cluster anions ( SO 2 ) 2 − and CO 3 − ( H 2 O ) n ( 0 ≤ n ≤ 3 ) have been accomplished for mass-selected ion species using an intracavity dye laser pumped with an argon-ion laser. in the case of CO 3 − , the unhydrated parent ion is observed to have a bound electronic excited state through which absorption of a second photon proceeds to a repulsive state leading to the ejection of O-. There are two possible mechanisms for CO 3 - hydrate dissociation: one is a repulsive and the second a predissociative mechanism. In both, cluster dissociation is initiated by the same 2 A 1 ← 2 B 1 transition from the ground to a weakly bound excited state of the core ion and leads to the loss of all water molecules within the time of observation. In the photodissociation of CO 3 - , CO 3 - ( H 2 O ) 1 , 2 , 3 , and ( SO 2 ) 2 - considerable excess energy is partitioned into relative translation of the photoproducts. Through studies of energy release in ( SO 2 ) 2 - with photons of parallel and perpendicular polarization, evidence has been obtained that the lifetime of the complex preceding photodissociation is less than a rotational period. The implications of the findings are discussed in terms of phase space theory.
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Castleman, A. W., C. R. Albertoni, K. Marti, D. E. Hunton, and R. G. Keesee. "Photodissociation dynamics of cluster anions." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.fc7.
Studies of the dissociation dynamics of cluster ions provide insight into the process of energy disposal for mass-selected species. Detailed investigations of the photodissociation of the cluster anions (SO2)2− and CO3−(H2O)n (0 ⩽ n ⩽ 3) have been accomplished for mass-selected ion species using an intracavity dye laser pumped with an argon-ion laser. In the case of CO3−, the unhydrated parent ion is observed to have a bound electronic excited state, through which absorption of a second photon proceeds to a repulsive state leading to the ejection of O−. There are two possible mechanisms for CO3− hydrate dissociation: one is a repulsive and the second a predissociative mechanism. In both, cluster dissociation is initiated by the same 2A1←2B1 transition from the ground to a weakly bound excited state of the core ion and leads to the loss of all water molecules within the time of observation. In the photodissociation of CO3−, CO3−(H2O)1,2,3, and (SO2)2− considerable excess energy is partitioned into relative translation of the photoproducts. Through studies of energy release in (SO2)2− with photons of parallel and perpendicular polarization, evidence has been obtained that the lifetime of the complex preceding photodissociation is less than a rotational period. The implications of the findings are discussed In terms of phase space theory.
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"Prediction of the conductivity and compatibility of the selected ionic liquids (ILs) with Nafion™ using COSMO-RS." In Sustainable Processes and Clean Energy Transition. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902516-51.
Abstract. Proton exchange membrane (PEM) electrolysis is one of the waters splitting techniques available for producing green hydrogen. As such, improvement of the membrane ion conductivity will result in improvement of hydrogen production. Ionic liquids have recently been reported to enhance ionic conductivity of PEM. Herein, a screening method to select suitable ionic liquids for the development of efficient proton exchange membrane. COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) was used to predict the ionic conductivity as well as the compatibility of the ions with the Nafion™ through the interpretation of σ-profile as well as interaction energy of the selected cations and anions. It was found that the anions namely of trifluoromethanesulfonate and nitrate with the cation of ammonium and imidazolium may be the best candidate for the ILs to be incorporated to Nafion™ for polymer electrolyte membrane (PEM) as the combination gives high ionic conductivity with considerable high interaction towards Nafion™. It is to be highlighted that the ionic liquids mainly interact with Nafion™ through the anion as implied by the high interaction energy of the anion towards Nafion™ compared to the cation.
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Teichmann, Maria, Sonja Draxler, Dietmar Kieslinger, and Max E. Lippitsch. "Fluorescence-lifetime-based sensors for anions." In BiOS '97, Part of Photonics West, edited by Richard B. Thompson. SPIE, 1997. http://dx.doi.org/10.1117/12.273552.
Pye, Cory. "Computational Chemistry Applied to Solutions: Anions." In Goldschmidt2022. France: European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.9429.
"Computational study of CO2 solubility in amino acid-based ionic liquids using COSMO-RS." In Sustainable Processes and Clean Energy Transition. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902516-33.
Abstract. The carbon capture, use, and sequestration (CCUS) techniques are proven to be efficient at lowering the atmospheric concentration of carbon dioxide. Notwithstanding the advances in this area, there are still significant restrictions in carbon dioxide (CO2) capture techniques in industry such as high capital costs, solvent evaporation losses, and low absorption and desorption rates. Ionic liquids (ILs) have received much interest as green solvent due to the benefits of their distinctive properties such as low vapor pressure and their capacity to capture CO2 making them a suitable replacement for present solvents, such as amines. Amino acid based ILs having close similarity with the alkanolamines may potentially have high affinity for CO2 absorption. Nevertheless, available database on these ILs is still limited and only focus on the common types of amino acids. Therefore, this paper aims to predict the CO2 absorption of different amino acid-based ionic liquids as cation/anion using quantum chemical calculation tools namely Conductor like Screening Model for Real Solvents (COSMO-RS) and TURBOMOLE. We evaluated 84 different ILs of different cations and anions based on their CO2 capacity, activity coefficient at infinite dilution (γ∞), and Henry’s constant (H). The results showed that amino acid as anions significantly enhanced the CO2 solubility compared to amino acid as cations. However, glycinium tetrafluoroborate [Gly+][BF4] showed high affinity for CO2 absorption compared to other amino acid-cations based with activity coefficient at infinite dilution (γ∞) = 0.117 and (H) = 8.07. We showed that the selection of anions/cations can significantly change the CO2 capacity in ILs.
Reports on the topic "Anions":
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Shukla, Manoj K., Luidmyla K. Sviatenko, Sergly I. Okovytyy, Danuta Leszczynska, and Jerzy Leszczynski. Catalytic Role of Solvated Electron in the Spontaneous Degradation of Insensitive Munition Compounds : Computational Chemistry Investigation. Engineer Research and Development Center (U.S.), July 2021. http://dx.doi.org/10.21079/11681/41122.
The DNAN (2,4-dinitroanisole), NTO (3-nitro-1,2,4-triazol-5-one), and NQ (nitroguanidine) are important insensitive energetic materials used in military applications. They may find their way to the environment during manufacturing, transportation, storage, training, and disposal. A detailed investigation of possible mechanisms for self-degradation of radical-anions formed by addition of solvated electron to DNAN, NTO, and NQ species was performed by computational study using the PCM(Pauling)/M06-2X/6-311++G(d,p) approach. Obtained results suggest that only NQ radical-anion is able for self-degradation by elimination of nitrite anion. Formation of urea radical on the earlier stage of the NQ radical-anion degradation was also predicted.
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Jonathan L. Sessler. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance. Office of Scientific and Technical Information (OSTI), September 2007. http://dx.doi.org/10.2172/891664.
Moyer, Bruce a., Debra A. Bostick, Christopher J. Fowler, Hyun-Ah Kang, Alexandre Ruas, Laetitia H. Delmau, Tamara J. Haverlock, et al. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance. Office of Scientific and Technical Information (OSTI), September 2005. http://dx.doi.org/10.2172/893098.
Bowman-James, Kristin, George S. Wilson, and Bruce Moyer. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance. Office of Scientific and Technical Information (OSTI), June 2001. http://dx.doi.org/10.2172/834750.
Bowman-James, Kristin, George S. Wilson, and Bruce Moyer. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance. Office of Scientific and Technical Information (OSTI), June 2002. http://dx.doi.org/10.2172/834752.
Bowman-James, Kristin, and George S. Wilson. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance. Office of Scientific and Technical Information (OSTI), June 2003. http://dx.doi.org/10.2172/834754.
Bowman-James, K., G. Wilson, and B. A. Moyer. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance. Office of Scientific and Technical Information (OSTI), December 2004. http://dx.doi.org/10.2172/835027.
Bowman-James, Kristin, and Bruce A. Moyer. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance. Office of Scientific and Technical Information (OSTI), June 2004. http://dx.doi.org/10.2172/838638.
Bowman-James, Kristen. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance. Office of Scientific and Technical Information (OSTI), December 2004. http://dx.doi.org/10.2172/850320.
Castleman, A. W., and Jr. Studies of Oxide Anions. Fort Belvoir, VA: Defense Technical Information Center, June 1991. http://dx.doi.org/10.21236/ada236812.
